1. FIELD OF THE INVENTION
This invention relates to the field of exercise equipment, and particularly to an apparatus for exercising the biceps and/or triceps muscles.
2. PRIOR ART
Weightlifting machines for exercising various muscle groups of the body are well-known. Such machines, particularly those intended for use by serious body builders, have become highly specialized. Some machines are designed to isolate a single muscle for exercise. For example, individual exercise machines are available for exercising only the biceps or triceps muscles of the arm. Prior exercise machines for exercising a single muscle typically have an exercise member that rotates about a single pivot.
Certain muscles of the human body are involved when limbs are moved at more than a single joint. For example, the biceps and triceps muscles are located between the elbow and shoulder joints. Typical prior art exercises for these muscle groups restrict movement of the arm to the elbow joint only. While movement at the elbow joint causes the greatest contraction of these muscles, the biceps muscle can also be exercised by locking the elbow joint and lifting the arm against resistance by rotation solely at the shoulder joint. Likewise, the triceps muscle can be exercised by locking the elbow joint and pushing down against resistance with rotation solely at the shoulder joint. However, the biceps and triceps muscles can be more completely and effectively exercised when both the elbow and shoulder joints are rotated with a large degree of rotation at the elbow joint and a proportionately smaller amount of rotation at the shoulder joint.